Pope John XIII

Pope John XIII (910-6 September 972) was Pope from 965 to 972, succeeding Pope Leo VIII and preceding Pope Benedict VI.

Biography
Giovanni Crescentius was the son of the elder Giovanni Crescentius, a duke who was allied with Count Theophylact I of Tusculum. John became pope in 965, and during his rule he gave the House of Crescentius more power and limited the power of the nobles. A rebellion in Rome broke out, and Roman militia captured him on 16 December 965, and he was later moved to Campagna out of fear that John's followers would free him. In 966 Otto I of Germany invaded Italy, reinstalling John XIII, and John sided with Otto during the rivalry between the Holy Roman Empire and Byzantine Empire. He humiliated Nicephorus II of Byzantium by calling him "Emperor of the Greeks" and not "Emperor of the Romans" while working together with Otto to secure a marriage alliance between one of Otto's sons and a Byzantine princess, and Nicephorus sent a threatening letter back to him, not even written by his hand. In 969 John I of Byzantium became emperor and agreed to the marriage, however. John died in 972.